In vitrostudy of interaction of synaptic vesicles with lipid membranes

Effect of PIP2 on Bilayer Structure and Phase Behavior of DOPC: An X‐ray Scattering Study

“…This observation is in line with our recent study on solid-supported single lipid bilayers and monolayers at the air/water interface, where a decrease of head-group electron density of single DOPC bilayers on solid support on addition of PIP 2 was observed. [16] Other X-ray scattering studies on lipid membranes of mixed systems such as DPPC/DPPS and DOPC/DOPS have shown similar effects. [33,34] Besides electrostatic effects, the molecular structure of PIP 2 could also contribute to the observations.…”

“…[15] In a recent study using a Langmuir trough we observed that PIP 2 enhances the interaction of SVs with a phosphatidylcholine lipid monolayer at the air/water interface. [16] Here, as a further step to elucidate the role of PIP 2 , we focus on its effect on bilayer structure and phase behavior of dioleoyl-sn-glycero-3-phosphatidylcoline (DOPC) bilayer stacks. To this end, we prepared oriented model membrane stacks formed by zwitterionic DOPC and variable molar fractions of anionic lipid PIP 2 .…”

Stalk formation as a function of lipid composition studied by X-ray reflectivity

“…Chol was previously shown to promote the stalk phase in pure DOPC [2] in agreement with [59,60]. PIP 2 , which enhances the interaction of synaptic vesicles with a phosphatidylcholine lipid monolayer at the air/water interface [15], was also shown to promote the stalk phase in PC, as well as the hexagonal phase at higher concentration [14]. We investigate how the critical value RH ⁎ of the phase transition between the L-phase and the Rphase shifts, i.e.…”

X-Ray Microscopy for Neuroscience: Novel Opportunities by Coherent Optics

“…The resulting profile ρ(r) of SV yielded structural parameters of the protein layers, as well as the polydispersity function p(R), derived with no free prefactors on absolute scale, and confirmed the main aspects of recent numerical modeling [85], based on the crystal structures of the constituent proteins and stoichiometric analysis. By using mixed suspensions of SV and proteoliposomes, fusion and interactions of SV can be evidenced on a structural level by SAXS [86,87]. Vesicle-membrane interaction was studied using X-ray diffraction and a Langmuir film balance with lipid monolayers of controlled composition, adjustable pH and salt concentration, and the SV solution injected in the sub-phase [88], a model system contributing to a molecular understanding of the interaction of synaptic vesicles with the inner leaflet of the synaptic membrane.…”

“…They probe Fourier components of the average structure in hydrated physiological states and are compatible with a multitude of sample environments. They yield only the ensemble [87,88]. (e) Grazing incidence diffraction results indicating the acyl chain ordering in the film, for different lipid mixtures (shifted for clarity, from top to bottom): pure DPPC monolayer, DPPC after injection of SVs, DPPC/PIP2, and DPPC/PIP2 with SVs.…”